Re: [Bug #13319] Page allocation failures with b43 and p54usb

[Pekka Enberg]

Hi Larry,

On Sun, Jun 7, 2009 at 4:10 PM, Larry Finger <Larry.Finger@xxxxxxxxxxxx> wrote:
> Rafael J. Wysocki wrote:
>> This message has been generated automatically as a part of a report
>> of recent regressions.
>>
>> The following bug entry is on the current list of known regressions
>> from 2.6.29.  Please verify if it still should be listed and let me know
>> (either way).
>>
>>
>> Bug-Entry     : http://bugzilla.kernel.org/show_bug.cgi?id=13319
>> Subject               : Page allocation failures with b43 and p54usb
>> Submitter     : Larry Finger <Larry.Finger@xxxxxxxxxxxx>
>> Date          : 2009-04-29 21:01 (40 days old)
>> References    : http://marc.info/?l=linux-kernel&m=124103897101088&w=4
>> Handled-By    : Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
>
> This bug is extremely difficult to pin down. I cannot reproduce it at
> will. The system has to be up for a long time, which is difficult with
> testing the late RC's of 2.6.30 and the code in wireless-testing so
> that new bugs don't end up in 2.6.31-RCX. That said, it still was in
> 2.6.30-RC6 and I'm not aware of any changes since that would fix it.
>
> My operating kernel is patched with additional diagnostics to help me
> understand why a kmalloc request for a buffer of 1390 bytes suddenly
> ends up as an O(1) request. Unfortunately, I don't have any answers.

Looking at the out-of-memory trace, there's still memory available but
the pskb_expand_head() allocation is GFP_ATOMIC so there's not much
the page allocator can do here. The amount of memory consumed by
inactive_file is pretty high so maybe the problem is related to the
recent mm/vmscan.c changes. Lets copy some more mm developers and see
if they can help out.

                        Pekka
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